Scanning probe microscope and specimen observation method and semiconductor device manufacturing method using said scanning probe microscope

ABSTRACT

In order to provide a scanning probe microscope capable of measuring with high throughput distribution information relating to local characteristics of a sample concurrently with accurate three-dimensional shape information of the sample without damaging the sample, the speed of approach to each measurement location is increased by controlling the approach of the sample and probe by the provision of a high-sensitivity proximity sensor of the optical type. Also, additional information relating to the distribution of material quality on the sample can be obtained without lowering the scanning speed by: applying a voltage to the probe, or measuring the response on vibrating the probe, or detecting the local optical intensity of the sample surface concurrently with obtaining sample height data and concurrently with the contact period with the sample, whilst ensuring that the probe is not dragged over the sample, by bringing the probe into contact with the sample intermittently.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a scanning probe microscope andspecimen observation method and semiconductor device manufacturingmethod using said scanning probe microscope.

2. Description of the Related Art

An example of known technology for measuring minute three-dimensionalshapes is provided by an SPM (scanning probe microscope). This is awidely employed technique whereby minute three-dimensional shapes of theatomic order can be measured, by scanning a sample whilst maintainingthe contacting force at an extremely small value while controlling aprobe with a sharp tip. Various improvements have previously been madedirected at the problem, characteristic of scanning probe microscopes,that it is difficult to raise the speed of physical scanning of thesample.

For example, in Laid-open Japanese Patent Publication Number H.10-142240 and Laid-open Japanese Patent Publication Number 2000-162115,a technique is disclosed for correcting shape data from both a probeflexure signal and a sample drive signal, in order to obtain bothimproved speed and better resolution. Also, in Laid-open Japanese PatentPublication Number H. 6-74754, a technique is disclosed of bringing upthe probe at high speed whilst vibrating the probe until it is close tothe sample, from a location that separated therefrom by about 5micrometers, by utilizing a construction such that the probe amplitudecan be reduced by acoustic interaction when the sample is approached, inorder to bring the probe up close to the sample at high speed. However,the above technique is subject to the problem that it can only beemployed in a scanning probe microscope of a construction in which theprobe is vibrated and to the problem that a further separate sensor mustbe provided in order to bring the probe up at high speed to a distanceof a few micrometers, since proximity cannot be sensed unless the probeis no more than a few micrometers from the sample.

Currently, also, dimension control using a CD-SEM (distance-measurementSEM) is performed in the process of forming a fine pattern on an LSI,but the following restrictions are encountered as the fineness of thepattern is increased. (1) Problem of measurement accuracy: the gatewidth of a 90-nm node LSI, which is expected to become the most commontype in 2003, is 80 nm; assuming that the allowed variability is 10% andthat the measurement accuracy is 20% thereof, the required measurementaccuracy is 1.6 nm. (2) Demand for profile measurement: the requirementfor APC (Advanced Process Control) in order to achieve high-accuracycontrol of line width is increased, but, in order to achieve this, atechnique for measurement of cross-sectional shape, whereby, in additionto pattern line width, electrical characteristics are greatlyinfluenced, becomes necessary. (3) Problem of the subject ofmeasurement: requirement for measurement of materials of low ability towithstand cathode rays, such as DUV (deep ultraviolet) resists, low-k(low permittivity) film materials is increasing. A similar requirementi.e. necessity of the same degree of measurement accuracy and forprofile measurement for measurement of resist patterns for masterproduction is anticipated in respect of measurement of the pits ofnext-generation high-density optical discs.

The above problems cannot be solved by current CD-SEMs. Scanning probemicroscopy is considered to be promising in this connection. What isrequired is a scanning probe microscope whereby, in addition to theimprovement in speed of probe approach described above, there is littledamage to soft and brittle materials and information regarding thematerial quality of the surface can be obtained.

In this connection, Laid-open Japanese Patent Publication Number H.11-352135 discloses a method of reducing damage to soft and brittlematerials and to the probe by scanning whilst the probe is cyclicallybrought up against the sample whilst the sample, or the probe, isvibrated with a fixed amplitude. In addition, Laid-open Japanese PatentPublication Number 2001-33373 discloses a scanning method wherein heightmeasurement is performed with the servo of the probe activated only atseparated measurement points, the probe being moved towards the nextmeasurement point in a raised condition. With this method, contactpressure is even smaller and damage to the soft and brittle material andto the probe is small. A further advantage is that faithful measurementof the shape of steps can be performed, since the probe is not draggedover the surface. However, although, when measurement of a pattern suchas that of a resist is to be performed, it is desirable to measure theshape of the pattern bottom and, in addition, to obtain by measurementinformation as to whether any of the resist is left at the bottom, thismethod was not able to meet these requirements. Also, it is necessary toraise the resonance frequency of the probe and reduce the inertia of theprobe in order to achieve higher speeds, and, with this in view, it wasnecessary to make the cantilever section at the tip of the probe small.However, with the conventional optical lever system, an area of theorder of 50 micrometers is necessary in order to ensure and adjust areflective surface for the laser, so there were limitations to theextent to which improvement in speed could be achieved.

As described above, with the prior art, there were problems concerningincreasing the speed of approach of the probe to the sample in order toimprove measurement throughput.

SUMMARY OF THE INVENTION

The present invention provides a scanning probe microscope and aspecimen observation method using this wherein a high-speed proximitysensor is provided and enabling a high speed of approach of the probe tothe sample, by arranging to perform approach of the probe to the sampleat high speed by providing the scanning probe microscope with aproximity sensor of high sensitivity having an optical height detectionfunction.

Also, a scanning probe microscope according to the present invention isconstituted such that additional information relating to thedistribution of material quality on the sample can be obtained withoutlowering throughput by: applying a voltage to the probe, or measuringthe response on vibrating the probe, or detecting the local opticalintensity of the sample surface concurrently with obtaining sampleheight data and concurrently with the contact period with the sample,whilst ensuring that the probe is not dragged over the sample, bybringing the probe into contact with the sample intermittently. In thisway, it is made possible to obtain the distribution of additionalinformation, namely, electrical capacitance, elasticity and opticalproperties in respect of the sample material quality concurrently withthe three-dimensional image and without lowering throughput,concurrently with the obtaining of a three-dimensional image using ascanning system with little damage to a brittle sample such as a resistpattern.

Also, according to the present invention, a scanning probe microscope isprovided that is easily adjustable and wherein flexure can be detectedeven with only a small cantilever size of the probe tip, in order tospeed up scanning.

Also, according to the present invention, in a scanning probemicroscope, accurate measurement of the shape of a step location is madepossible by performing scanning with the probe inclined, in respect ofsample step locations of steep inclination.

Furthermore, according to the present invention, in a method ofmanufacturing a material having an ultra-fine structure such as asemiconductor device, stable device fabrication of an ultra-finestructure such as that of a semiconductor device is made possible byobserving the semiconductor pattern or the resist pattern using ascanning probe microscope as described above and feeding back theresults of this observation to the operating conditions of the processapparatuses.

These and other objects, features and advantages of the invention willbe apparent from the following more particular description of preferredembodiments of the invention, as illustrated in the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing the overall construction of a scanning probemicroscope;

FIG. 2 is a view to a larger scale of an embodiment of the vicinity ofthe probe;

FIG. 3 is a view showing an embodiment of an optical system;

FIG. 4 is a view showing a method of controlling a probe;

FIG. 5 is a view showing the construction of a cantilever capable ofcontrolling the inclination of the probe;

FIG. 6 is a view showing a condition in which the probe is vibratedduring the period of contact of the sample and the probe;

FIG. 7 is a view showing how measurement of sample height is performed,whilst high-frequency micro-vibrations are constantly being applied,with a period Tc that is considerably slower than the frequency of thesemicro-vibrations;

FIG. 8 is a view showing a method of high-speed approach control of theprobe-sample distance;

FIG. 9 is a view showing the principles of measurement of probe flexureby heterodyne interference;

FIG. 10 is a view showing an example of a resist pattern that can beidentified in accordance with the present invention; and

FIG. 11 is a view showing an example of an embodiment in which processcondition control of a semiconductor is performed in accordance with thepresent invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 is a view showing the construction of a scanning probe microscopeaccording to the present invention. FIG. 2 is a view to a larger scaleof an embodiment of the vicinity of the probe. The sample 501 is placedon a sample stage 302 that is capable of being driven in the X, Y and Zdirections under the control of a scanning control section 201. Abovethis there is arranged a probe 103; a probe movement mechanism 252 onwhich the probe 103 is mounted is driven in the X, Y and Z directionsunder the control of a probe drive section 202 and probe scanning of thescanning probe microscope is thereby conducted. 252 is mounted on aprobe holder 101; the probe holder 101 is mounted in the microscopecylinder 102 by means of a probe holder raising/lowering mechanism 253;coarse movement drive thereof in the Z direction is effected undercontrol of the probe holder drive section 203. The probe movementmechanism 252 is a fine movement mechanism; approach of the probe to thesample is effected by the probe holder raising/lowering mechanism 253such that the operating distance does not become too large.Alternatively, in another embodiment, approach of the probe to thesample may be effected by driving the sample stage 302. Also, probescanning of the scanning probe microscope may be effected by driving thesample stage 302.

The proximity sensor 204 is a sensor for measuring with high sensitivitythe height in the vicinity of the tip of the probe; approach to thesample can thereby be implemented at high speed without the probeabutting the sample, by controlling the speed of approach by detectingcontact of the probe with the sample in advance. As will be described,for the proximity sensor 204, light could be employed. However, anyother type of sensor could be employed so long as it has a detectionrange of at least some tens of micrometers and is capable of detectingthe distance to the sample with a sensitivity of the order of onemicrometer. For example, an electrostatic capacitative sensor whereindistance is detected by measuring the electrostatic capacitance byapplying an AC voltage between the sample holder 101 or the cantileversection of the probe 103 and the sample 501 or an air microsensor inwhich the pressure of air flowing between the sample holder 101 and thesample 501 is detected may be employed.

The scanning control section 201 effects approach of the probe andscanning of the sample etc by controlling a probe flexure detectionsensor 205, the proximity sensor 204, the probe holder drive section203, the probe drive section 202 and the sample stage 302. During thisprocess, an image of the surface shape of the sample is obtained bysending the signal of the sample during scanning to an SPM image-formingdevice 208. Also, a signal application device 207 measures theelasticity of the surface by using the flexure detection sensor 205 todetect the response of applying high-frequency vibrations to the probe,or measures the capacitance or resistance by measuring the currentobtained on application of AC or DC voltage between the probe and thesample. By performing this at the same time as probe scanning, apartfrom a surface shape image on the SPM image-forming device 207, anadditional image of distribution of properties can be obtained.

If an object lens is incorporated in the probe holder 101, simultaneousobservation of the SPM measurement area by obtaining an optical image ofthe sample by an optical image sensor 206 can be employed in adjustmentwhen mounting the probe 103.

The operation of the device as a whole is controlled by an overallcontrol device 209; acceptance of instructions from the operator andpresentation of an optical image or SPM image can be achieved by meansof a display/input device 251 thereof.

FIG. 3 is a view showing an embodiment of an optical system. Lightemitted from a light source 111 is converted to a parallel beam by alens 112, reflected by a mirror 113, input to an object lens formedwithin the probe holder 101, and focused on the sample 501. An image ofany desired shape, such as a spot or a slit, can be formed by means ofthe shape of the aperture incorporated in the light source 111. Thelight reflected by the sample again passes through the object lens, isreflected by a mirror 114, and is imaged on a photodetector 116 by animaging lens 115. The position of the image is moved in accordance withthe height of the sample 501. If the angle of incidence of the detectionbeam 110 onto the sample is ?, the image magnification factor by thelens 115 is m and the sample height is Z, the amount of this movement is2mZ tan ?, so the height Z of the sample can be detected if the amountof this movement is measured. Any type of detector 116 that is capableof detecting image position may be employed, such as for example a PSD(position sensitive device), divided photodiode or linear image sensoretc.

Also, although, in the above description, the construction is such thatthe detection beam 110 passes through the object lens, considerationcould be given to a construction in which the detection beam 110 passesoutside the object lens and is bent by a further mirror, not shown,before being imaged on the sample. In this case, the lenses 112 and 115are respectively adjusted such that the light source 111 and the sensor116 are in an image-forming relationship with the sample 501. The amountof movement of the image on the sensor 116 is then 2mZ sin ?.

The probe flexure detection system will now be described. The lightissuing from the light source 131 passes through a lens 132 and a beamsplitter and then through a further beam splitter 134 before passingthrough an object lens whereby it is directed onto the cantileversection of the probe. The light which is reflected thereat returns bythe same path, passing through the beam splitter 133 and is directedonto the sensor 136 through the lens 135. The lens 135 is arranged suchthat the emission pupil of the object lens and the sensor 136 are in animage-forming relationship, so a change in position proportional to theinclination of the reflecting surface of the cantilever is therebyproduced in the beam on the sensor 136. It therefore becomes possible todetect the inclination (flexure) of the cantilever by detecting thisusing a PSD (position sensitive device), divided photo diode or linearimage sensor etc arranged at the position of 136.

In addition to flexure, it is also possible to simultaneously detecttorsion by employing a two-dimensional PSD, image sensor or photodiodedivided into four. In order to separate this detection beam 130 from thebeam of the sample observation system, preferably the light source 131is a monochromatic laser and interference filters are provided beforeand after the lens 135 so as to permit the passage of this beam only.

Efficiency may be further improved by using a dichroic mirror as thebeam splitter 134. Also, if the beam splitter 133 is a polarizing beamsplitter and the direction of polarization of the laser 131 is Spolarization, which is reflected by 133, and a ¼ wavelength plate (notshown) is arranged between the beam splitters 133 and 134, the Spolarized light may be converted to circularly polarized light beforestriking the reflecting surface of the probe 103 so that, by using a ¼wavelength plate, the reflected beam therefrom is then again convertedto P polarized light which passes through the polarizing beam splitter133.

In the sample observation system, emission is effected from anilluminating light source 154, passes through a condenser lens 153, isreflected by a beam splitter 155, passes through the beam splitter 134,passes through an object lens within 101 and illuminates the sample 501.The reflected light from the sample again passes through an object lensand is imaged by an imaging lens 152 by passing through the beamsplitters 134 and 155 before being detected by an image sensor 151.

Also, as described using FIG. 3, by constituting the probe, sampleobservation system, sample height sensor and probe flexure detectionoptical system coaxially, simultaneous observation of the SPMmeasurement device, facilitation of probe adjustment and high-speedapproach of the probe and sample can be achieved. Also, by arranging theprobe flexure detection optical system coaxially, it becomes possible todirect a detection beam 130 even onto a probe having a cantileversection of small width, making it possible to employ a probe which islighter and of higher resonance frequency, thereby enabling the speed ofscanning to be increased. By arranging for detection to be effected inall cases through the object lens 101, it becomes possible to make theobject lens approach the probe closely, making possible opticalobservation of the sample with high resolution. Also, an off-axisconstruction of at least one of the sample height sensor and probeflexure sensor in which light is projected and detected in inclinedfashion through the gap between the object lens and the sample, using anobject lens of long working distance, may of course be considered.

Also, as another construction, a method may be considered in whichflexure of the probe 103 is detected using a heterodyne interferencemethod. A point light source of frequency fo and a point light source offrequency fo+f obtained by shifting this frequency by a frequency f arearranged at the position of the light source 131. Provision of a pointlight source may be achieved by restricting the width of a laser beam byusing a lens or by arranging the emission terminal of an optical fiberat this point. The optical system is adjusted so as to form this imageat two points on the probe 103.

As shown in FIG. 9, one of the images is formed at the tip of thecantilever section of the probe while the other image is formed at theroot thereof; their reflected beams intersect at a position 136, so if aphotodiode is placed at 136, beats of frequency f are generated byinterference of these two beams. When this beat signal is subjected tolock-in detection, taking as reference the frequency f that is appliedto the frequency shifter, and the phase thereof is found, the change inphase thereof i.e. the change of inclination of the cantilever isobtained. The flexure of the cantilever can thereby be detected.Alternatively, instead of the signal that is applied to the frequencyshifter, light transmitted by the beam splitter 133 without reflectionafter passing through the lens 132 may be detected by a furtherphotodiode (not shown) at the location where the two beams cross andtaken as the reference signal of frequency f.

Also, in another construction, a sensor whereby a signal is obtainedthat reflects changes of strain, such as a strain gauge, may beincorporated in the probe and employed instead of the optical flexuresensor.

High-speed approach control of the probe and the sample employing asample height sensor according to the present invention is describedbelow with reference to FIG. 8. First of all, the probe micro-movementmechanism (probe movement mechanism 252) is put in extended condition(condition in which the probe micro-movement height is low). Next, theprobe coarse movement mechanism (probe holder raising/lowering mechanism253) lowers the probe (lowers the probe coarse movement height) at highspeed (of the order of 1 to 10 mm/s) whilst the sample height sensor 204is monitored. When the output of the sample height sensor 204 has become10 to a few tens of micrometers, a changeover to low-speed approach iseffected (of the order of 0.1 mm/s). The output of the probe flexuredetection sensor 205 is monitored and, at the point where this starts tobecome large, the probe micro-movement mechanism is straightawayretracted (high-speed probe retraction in FIG. 8).

Compared with the method that is ordinarily carried out, in whichapproach is performed with the probe put in the SPM servo mode, in whichit is difficult to raise the speed during low-speed approach owing tothe restriction to the zone of probe control, this has the advantagethat the speed of low-speed approach is raised by straightawayretracting the probe at the instant where contact is sensed, withoutputting the probe into the servo mode. After this, after high-speedprobe retraction has been performed, the servo is turned ON and theprobe is slowly brought into contacting condition with respect to thesample. Although the foregoing description has been given under theassumption that the probe side is driven, it of course applies in thesame way in the case where probe approach is effected by driving thesample stage 302.

Next, a probe scanning mode applied to measurement of a sample of softbrittle material having a high aspect ratio, such as a resist pattern,is described with reference to FIG. 4. The sample height, exclusively atdiscrete measurement points, is then measured by repeating the operationof turning on the servo (Tc interval) such as to provide a fixed contactpressure (i.e. probe flexure), by raising and lowering the probe, asshown in (b), whilst changing the relative position of the sample andthe probe in the horizontal direction. The repetition period is Ts. Inthis way, since the probe is not dragged over the sample, there islittle damage to the sample and probe scanning can be implementedwhereby the shape can be faithfully measured even at step locations.This itself is a method which is disclosed in Laid-open Japanese PatentPublication Number 2001-33373 etc, but the following invention isdescribed as an embodiment applied to measurement of for example resistpatterns.

The probe tip has a certain taper angle, so conventionally it was notpossible to measure accurately with a scanning probe microscope theshape of a step location elevated therefrom; however, when a step isdetected, scanning is arranged to be performed with the probe inclinedas shown by the dotted line in (a). As methods of inclining the probe,methods are available in which the probe holder is provided with amicro-rotation mechanism; however, there is also available the method ofemploying a piezoelectric thin film type cantilever, as shown in FIG. 5,as disclosed in “T. R. Albrecht, S. Akamine, M. J. Zdeblick, C. F.Quate, J. Vac. Sci. Technol. A8 (1), 317 (Januay/February, 1990)”. Thisis of a so-called bi-morph construction, in which piezoelectric elementsare provided above and below an intermediate electrode G, whileelectrodes A, B, C, D are formed on the opposite side thereof. With thisconstruction, the probe can be inclined by generating torsionaldeformation when a voltage change is applied in opposite directions toA-G, D-G and B-G, C-G. Torsion of the probe can be easily detected byemploying a 4-sector divided photodiode for the probe flexure detector136.

In addition, in resist pattern measurement, there is a considerable needto detect whether any resist is left at the bottom of a resist pattern.Also, in recent years semiconductors with flat structure have becomecommon and the need to ascertain the material quality boundary inrespect of patterns in which surface irregularity has been eliminated bygrinding has increased. In order to meet these needs, concurrently withthe measurement of the shape of three-dimensional surfaces, techniquesfor measuring the distribution of surface capacitance, opticalcharacteristics and mechanical properties such as elasticity arerequired.

With the scanning system described in FIG. 4(b), there is an interval Tcin each measurement period Ts in which the probe is in contact with thesample surface, so measurements of the distributions of various physicalproperties can be performed concurrently with that of the image of thesurface shape by performing measurements of these various surfacephysical properties in synchronization with these intervals. FIG. 4(c)is an embodiment in which measurement of local capacitance is performedby synchronized detection of the current that flows when an AC voltageis applied between the probe and the sample. Also, FIG. 4(d) is anembodiment in which the distribution of local optical properties of thesample is found by making the interior of the probe capable oftransmitting light, illuminating the sample and guiding the light fromthe tip of the probe to an optical fiber 170 and thence, through a lens171, to a sensor 172 that detects the amount of light in the intervalTc. In this way, observation/measurement can be conducted even inrespect of a sample wherein for example silicon oxide is buried insilicon, as shown in FIGS. 4(c) and (d) and the surface rendered flat bygrinding.

FIG. 6 shows an embodiment in which the probe is subjected tomicro-vibration with period T in the interval Tc. It will be assumedthat T is considerably smaller than Ts or Tc. The distribution of localmechanical properties of the sample surface can be obtained by obtaininga probe flexure signal and performing synchronized detection on thisapplied input vibration signal to find the amplitude and phase thereof.It is also possible to find the distribution of local optical propertiesof the sample by illuminating the probe tip and conducting detectionsynchronized with probe vibration by detecting only scattered light atthe tip or by detecting light brought to convergence by the opticalsystem, as shown in FIG. 4(d).

Alternatively, as shown in FIG. 7, it is also possible to detect theheight of the sample by constantly applying vibration of period T (whereT<<Tc) to the probe and detecting reduction of the amplitude resultingfrom contact of the probe with the sample.

Next, an example of measurement of a resist pattern will be describedusing FIG. 10. In the measurement of a resist pattern, is necessary todistinguish whether the pattern has been broken vertically, as in (a),whether a thin resist layer has been left behind, as in (b), or whetherthe bottom portions of the grooves or holes have been reduced in width,as in (c). These can be distinguished according to the presentinvention.

In addition, a method of device fabrication using the present inventionis shown in FIG. 11. Devices are formed by feeding wafers 620 to processapparatuses 601, 601′. The process apparatuses 601, 601′ may be,depending on the case, etchers, CMP apparatuses, exposure apparatuses ordeveloping apparatuses. The scanning probe microscope 603 according tothe present invention is used to observe/measure the patterns formed onwafers, using wafers extracted from the process steps or dummy wafers621. Alternatively, with large throughput, all of the wafers may besubjected to observation/measurement by the scanning probe microscope603 according to the present invention.

Since, with the present invention, the distribution of surfaceconditions and/or three-dimensional shape of the pattern can beobserved/measured accurately without damaging the sample, fabrication ofdevices of high precision in a stable fashion can be achieved by feedingback the observation/measurement results to the process conditions ofthe process apparatuses 601, 601′. Depending on the situation, aspecial-purpose data processing server may be interposed in the feedbackpath 610.

Processing can also be performed by feeding the data obtained byobservation/measurement with the scanning probe microscope 603 accordingto the present invention through a circuit to another data processingdevice, when they are combined with data obtained by otherinspection/observation/analysis apparatuses. For example, by combiningand analyzing the data obtained by observation/measurement with thescanning probe microscope 603 of the present invention with sampleanalysis data obtained by another analysis apparatus, more detailedinformation such as the two-dimensional or three-dimensionaldistribution of defects or composition of the sample surface may beobtained.

According to the present invention, measurement throughput may beimproved since high-speed approach of the sample and probe can beachieved by the provision of a high-sensitivity proximity sensor.

Also, according to the present invention, additional informationrelating to the distribution of material quality on the sample isobtained without lowering of throughput, concurrently with obtainingsample height data, whilst ensuring that the probe is not dragged overthe sample by bringing the probe into contact with the sampleintermittently.

Also, according to the present invention, in regard to sample steplocations of steep inclination, accurate measurement of shape at steplocations can be achieved by performing scanning with the probeinclined.

Also, according to the present invention, high-precision devicefabrication can be achieved in stable fashion, since the semiconductorpattern can be measured with high throughput.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is therefore to be considered in all respects as illustrativeand not restrictive, the scope of the invention being indicated by theappended claims rather than by the foregoing description and all changeswhich come within the meaning and range of equivalency of the claims aretherefore intended to be embraced therein.

1. A scanning probe microscope comprising: a sample stage on which asample is placed; a probe that measures surface distribution and/orthree-dimensional surface shape of a sample placed on this sample stage;a drive section that controls the mutual position of said sample stageand said probe; and a sensor that measures the contact condition of saidprobe and said sample; wherein said sensor measures the shape of a steepstep by inclining the probe at a step location of said sample.
 2. Ascanning probe microscope comprising: a sample stage on which a sampleis placed; a probe that measures surface distribution and/orthree-dimensional surface shape of a sample placed on this sample stage;a drive section that controls the mutual position of said sample stageand said probe; and a sensor that measures the contact condition of saidprobe and said sample; wherein said drive section has a scanning mode inwhich the height is measured by cyclically raising said probe andlowering it at the next measurement point and measurement of thethree-dimensional surface shape distribution and measurement of at leastone of the mechanical characteristics, optical characteristics andelectrical characteristics of the sample are preformed during the periodin which said probe is made to contact said sample.
 3. A method ofobserving a sample wherein a semiconductor pattern or resist pattern isobserved using a scanning probe microscope according to claim
 1. 4. Amethod of observing a sample wherein a semiconductor pattern or resistpattern is observed using a scanning probe microscope according to claim2.
 5. A method of manufacturing a semiconductor device wherein asemiconductor pattern or resist pattern is observed using a scanningprobe microscope according to claim 1 and the results are fed back tothe operating conditions of a process apparatus.
 6. A method ofmanufacturing a semiconductor device wherein a semiconductor pattern orresist pattern is observed using a scanning probe microscope accordingto claim 2 and the results are fed back to the operating conditions of aprocess apparatus.